FLUX.1 Kontext Style Transfer Guide for Controlled Edits

FLUX.1 Kontext is Black Forest Labs' image generation and editing family. Its hosted pro model accepts an image and a text instruction; style transfer is a use of that editing capability. Overview

What are the key facts about FLUX.1 Kontext style transfer?

Which style changes can FLUX.1 Kontext make?

BFL describes using an image as a style reference while generating a different scene. It also documents local edits and successive changes that preserve important visual context. Launch

For restyling an existing picture, make the desired visual treatment explicit. Name the medium, edge quality, palette and texture, then list the content that should survive the transformation.

For instance, you might request a screen-printed appearance with flat teal and cream areas while preserving a bicycle's frame shape and the position of its rider. This is an original prompting example, not a benchmark result.

BFL's style guidance discusses photographic and illustration treatments. Style guide

Use concrete descriptions to specify an observable target instead of asking only for a “better” or “more artistic” image.

Separate the style goal from the content goal in your review. A result can have convincing brushwork while changing the person's face or removing an object; those are different reasons to reject a candidate.

You can also use a reference's visual language for a new subject. Decide that intent before starting: preserving a scene and borrowing a reference style require different instructions about what the next image should contain.

What limits affect FLUX.1 Kontext style transfer?

Kontext pro's endpoint schema includes input_image plus input_image_2, input_image_3 and input_image_4; BFL labels the additional fields experimental multireference inputs. The example below uses one source image. Endpoint specification

For separate content and style references, name each image's intended role in your prompt and evaluate whether the output follows that assignment.

The API documents outputs around one megapixel. Uploading a detailed source image does not imply that every original pixel, texture or fine line will remain available in the result. Editing API

A preservation instruction expresses your target; it is not a pixel lock. Compare the entire result with the input, especially where the style transformation changes edges, facial features or small printed details.

The downloadable dev checkpoint is a separate model with its own license. The presence of dev weights does not make the hosted pro and max models downloadable or establish identical behavior across variants. Dev card

BFL now recommends FLUX.2 for new editing projects. Kontext remains relevant for an existing workflow, but use a current model comparison before selecting a service for a new application. Overview

How do you restyle an image with FLUX.1 Kontext?

Define the change and the preserved content

1. Choose the approved source image. Note the subject, viewpoint, pose and key objects that the restyled output must retain.
2. Describe one visual treatment. Specify a medium and a few visible properties, such as broad ink contours, muted colors or paper grain.
3. Write the preservation sentence separately. Include only constraints you can actually inspect in the source and output.
4. Generate a candidate and compare it with the source before requesting a second change.

Try: “Restyle this bicycle scene as a limited-palette screen print with teal and cream shapes and visible paper grain. Preserve the rider's pose, bicycle geometry, viewpoint and the position of the street sign.”

Avoid combining the first style experiment with a new camera angle and a new environment. Keeping the content brief stable makes it easier to understand whether the requested visual treatment is responsible for an unwanted change.

For a reference-led new image, state the new subject directly: “Use this reference's flat colors and broad ink outlines for a harbour scene with fishing boats.” Judge style resemblance separately from the new scene's composition.

Submit an image-editing request

In BFL Playground, select Kontext pro, upload your image and describe the change. Editing guide

For automation, configure BFL_API_KEY, install requests, and submit a base64-encoded source image to the documented endpoint. Endpoint specification

import base64
import os
from pathlib import Path
import requests

response = requests.post(
    "https://api.bfl.ai/v1/flux-kontext-pro",
    headers={"x-key": os.environ["BFL_API_KEY"]},
    json={
        "input_image": base64.b64encode(
            Path("source.png").read_bytes()
        ).decode(),
        "prompt": "Restyle as a teal and cream screen print. "
                  "Preserve the subject, pose and composition.",
    },
    timeout=60,
)
response.raise_for_status()
print(response.json()["polling_url"])

This submits the edit. Poll the returned URL until its status is Ready, then retrieve result.sample; handle a failed request before continuing. BFL's signed result URLs expire, so download approved results promptly. Editing API

For each candidate, inspect the face, silhouette and object positions first. Then assess whether the palette, marks and surface texture match your style request. Finally, compare small text and fine edges at useful viewing size.

If an object disappears, name it in the preservation sentence. If the style is weak, strengthen the medium description without adding scene changes. Keep the input constant while assessing the revision.

For a conversational interface to the same hosted model, see Kontext Chat. For a workflow using downloaded dev weights, start with the Kontext dev guide.

How does Kontext style transfer compare with Gemini?

The ComfyUI complete guide explains the graph workflow context for local experiments. Compare candidates using the same preservation requirements, regardless of interface.

What else should you know about FLUX.1 Kontext style transfer?

Is Kontext style transfer a separate model?

FLUX.1 Kontext style transfer uses the family's image-editing capabilities. Choose the actual model variant and supply a reference image with the desired transformation. Overview

Can I preserve the original composition?

For FLUX.1 Kontext style transfer, state which composition elements should remain and review the output against them. Start with a single style change so that framing, pose and object placement remain clear evaluation criteria.

Can I supply separate content and style images?

Kontext pro's endpoint schema provides a primary image field and three additional experimental reference-image fields. Describe which reference supplies the scene and which supplies the style, then check that distinction in the result. Endpoint specification

Does style transfer require fine-tuning?

BFL documents FLUX.1 Kontext image editing through instructions without fine-tuning. Start with a reference and a precise visual description, then evaluate whether the result meets your project's style requirements. Editing guide

Sources

• BFL Kontext introduction
• BFL Kontext overview
• BFL image-editing API documentation
• BFL Kontext pro endpoint specification
• BFL style and aesthetics guidance
• FLUX.1 Kontext dev model card
• Google Nano Banana editing examples

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